The invention relates to a process for preparing coated, thermosetting plastic foam having improved properties and articles so produced.
Thermosetting plastic foam is frequently used as material for articles, particularly in plates and building panels, for sound and heat isolation. Previously the use of such materials has been limited because of the combustibility and low strength of such plastic foams. In order to eliminate these drawbacks, it has been proposed to laminate one or both sides of these articles with paper, plastic sheeting, metal plates and metal sections, wood fiber board, gypsum board, or the like. Flame-extinguishing agents may be added to the foam-forming material to improve the fire resistance.
According to the present invention a thermosetting plastic foam provided on at least one surface with a coating layer can be obtained in the process of allowing a foam-forming composition to cure into a solid plastic foam on a suitable substrate, or in a suitable mold, while in contact with the coating-layer material, at least one surface of the foam being provided with a thin, continuous layer of inert material, which is connected to and integral with the foam. That is, the foam-forming composition is contacted with an evenly distributed layer of inert material consisting of non-coherent particles, at least at a point in time at which the foam-forming composition, or the resulting foam, is adhesive and partly penetrable to the particulate material.
In this way, objects, especially sheets of material can be obtained having a surface with strongly improved fire resistance and increased strength. The resulting product in sheet form, is particularly adapted for use as a construction panel to be applied, for instance, over existing walls as a sound/heat insulator.